U.S. patent application number 13/401344 was filed with the patent office on 2012-06-14 for fluidic distribution system and related methods.
This patent application is currently assigned to Societe BIC. Invention is credited to Gerard F. McLean, Jeremy Schrooten, Paul Sobejko, Joerg Zimmermann.
Application Number | 20120148932 13/401344 |
Document ID | / |
Family ID | 39827224 |
Filed Date | 2012-06-14 |
United States Patent
Application |
20120148932 |
Kind Code |
A1 |
McLean; Gerard F. ; et
al. |
June 14, 2012 |
FLUIDIC DISTRIBUTION SYSTEM AND RELATED METHODS
Abstract
Embodiments of the present invention relate to a fluid
distribution system. The system may include one or more
electrochemical cell layers, a bulk distribution manifold having an
inlet, a cell layer feeding manifold in direct fluidic contact with
the electrochemical cell layer and a separation layer that
separates the bulk distribution manifold from the cell feeding
manifold, providing at least two independent paths for fluid to
flow from the bulk distribution manifold to the cell feeding
manifold.
Inventors: |
McLean; Gerard F.; (West
Vancouver, CA) ; Zimmermann; Joerg; (Vancouver,
CA) ; Schrooten; Jeremy; (Mission, CA) ;
Sobejko; Paul; (North Vancouver, CA) |
Assignee: |
Societe BIC
North Vancouver
CA
Angstrom Power Incorporated
|
Family ID: |
39827224 |
Appl. No.: |
13/401344 |
Filed: |
February 21, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12053408 |
Mar 21, 2008 |
8133629 |
|
|
13401344 |
|
|
|
|
60919470 |
Mar 21, 2007 |
|
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Current U.S.
Class: |
429/443 ;
429/458 |
Current CPC
Class: |
H01M 8/04089 20130101;
H01M 8/2483 20160201; Y02E 60/50 20130101; H01M 8/0258 20130101;
H01M 2250/30 20130101; H01M 8/04201 20130101; H01M 8/241 20130101;
Y02B 90/10 20130101; H01M 8/04753 20130101; H01M 8/24 20130101 |
Class at
Publication: |
429/443 ;
429/458 |
International
Class: |
H01M 8/24 20060101
H01M008/24; H01M 8/04 20060101 H01M008/04 |
Claims
1. A fuel cell system comprising: a bulk distribution manifold
configured to contain fluid at a first pressure, wherein the bulk
distribution manifold includes an inlet; a feeding manifold
configured to contain fluid at a second pressure that is less than
the first pressure; a separation layer disposed between the hulk
distribution manifold and the feeding manifold, wherein the
separation layer defines at least two independent fluid flow paths,
each of the fluid flow paths spanning through the separation layer
and fluidly communicating with both the bulk distribution manifold
and the feeding manifold; and a planar fuel cell layer, the planar
fuel cell layer including an array of unit fuel cells, wherein the
planar fuel cell layer is in direct fluid contact with the feeding
manifold.
2. The fuel cell system of claim 1, wherein the feeding manifold is
defined at least in part by the separation layer and the planar
fuel cell layer and wherein the bulk distribution manifold is
defined at least in part by the separation layer.
3. The fuel cell system of claim 1, wherein the separation layer is
sealed to the planar fuel cell layer.
4. The fuel cell system of claim 1, wherein the feeding manifold
includes at least two discrete regions, each region served by at
least one independent fluid flow path.
5. The fuel cell system of claim 1, further including fluid
contained within the bulk distribution manifold at the first
pressure and fluid contained within the feeding manifold at a
second pressure.
6. The fuel cell system of claim 1, wherein the layered fluid
distribution system is a component of a portable electronic
device.
7. The fuel cell system of claim 1, wherein each of the independent
fluid flow paths includes a fluidic controller, and wherein each
fluidic controller is configured to regulate flow of fluid from the
first pressure to the second pressure.
8. The fuel cell system of claim 1, wherein the fluid distribution
system includes more than one planar fuel cell layer.
9. The fuel cell system of claim 1, further comprising a fluid
reservoir in fluid communication with the bulk distribution
manifold.
10. The fuel cell system of claim 9, further including a primary
pressure regulator coupled to the inlet.
11. The fuel cell system of claim 9, wherein the feeding manifold
is defined at least in part by the separation layer and the fuel
cell layer and wherein the bulk distribution manifold is defined at
least in part by the separation layer.
12. The fuel cell system of claim 1, wherein the planar fuel cell
layer includes a plurality of anodes, a plurality of cathodes, and
an ion-conducting electrolyte, wherein the plurality of anodes are
arranged adjacently on a first side of the planar fuel cell layer
and the plurality of cathodes are arranged adjacently on a second
side of the planar fuel cell layer opposite the first side,
13. The fuel cell system of claim 12, wherein the first side of the
planar fuel cell layer and the feeding manifold define a fuel
plenum.
14. The fuel cell system of claim 1, wherein the feeding manifold
and the planar fuel cell layer at least partially define a fuel
plenum.
15. A method of generating power, the method comprising: providing
a fuel cell system that includes a bulk distribution manifold,
wherein the bulk distribution manifold includes an inlet; a feeding
manifold; a separation layer disposed between the bulk distribution
manifold and the feeding manifold, wherein the separation layer
defines at least two independent fluid flow paths, each of the
fluid flow paths spanning through the separation layer and
communicating with both the bulk distribution manifold and the
feeding manifold; and one or more planar fuel cell layers, each
planar fuel cell layer including an array of unit fuel cells;
directing fuel through the inlet and into the bulk distribution
manifold at a first pressure; directing the fuel in the bulk
distribution manifold through the independent fluid flow paths and
into the feeding manifold; and contacting the one or more fuel cell
layers with the fuel in the feeding manifold, wherein the fuel
contacts the one or more fuel cell layers at a second pressure,
wherein the first pressure is greater than the second pressure.
16. The method of claim 15, wherein the one or more planar fuel
cell layers includes a plurality of anodes, a plurality of
cathodes, and an ion-conducting electrolyte, wherein the plurality
of anodes are arranged adjacently on a first side of the planar
fuel cell layer and the plurality of cathodes are arranged
adjacently on a second side of the planar fuel cell layer opposite
the first side, and wherein contacting the one or more fuel cell
layers with the fuel in the feeding manifold comprises contacting
the plurality of anodes of the one or more planar fuel cell layers
with the fuel in the feeding manifold.
17. The method of claim 16, wherein the fuel cell system is a
component of a portable electronic device and contacting the one or
more fuel cell layers with the fuel produces power for the
electronic device.
18. The method of claim 17, further including a fuel reservoir in
fluid communication with the inlet.
19. The method of claim 15, wherein the feeding manifold is defined
at least in part by the separation layer and the one or more fuel
cell layers and wherein the bulk distribution manifold is defined
at least in part by the separation layer.
20. The method of claim 17, wherein the separation layer is sealed
to the one or more planar fuel cell layers.
21. The method of claim 15, wherein each of the independent fluid
flow paths includes a fluidic controller, and wherein each fluidic
controller is configured to regulate flow of fluid from the first
pressure to the second pressure.
22. The method of claim 15, wherein the feeding manifold includes
at least two discrete regions, each region served by at least one
independent fluid flow path.
Description
[0001] This application is a continuation application of U.S.
patent application Ser. No. 12/053,408, filed Mar. 21, 2008, which
application claims the benefit of priority under 35 U.S.C.
.sctn.119(e) to U.S. Provisional Patent Application Ser. No.
60/919,470, filed Mar. 21, 2007, which applications are hereby
incorporated by reference in their entirety.
BACKGROUND
[0002] Electronic components, such as electronic devices, are
trending to become smaller in size while increasing in performance
technology. Other applications facilitating electrochemical cell
power supplies demand high output or high efficiency. As electronic
components are designed smaller in size, incorporate sophisticated
and complex technology, require high power density and high level
of control and efficiency, the demands on the associated power
supply become greater. Further, the additional technology may
require that the power supply last for longer periods of time or
that power be delivered at uniform rates for steady electronic
component performance.
[0003] One example of a power supply is a fuel cell system. A fuel
cell system may include one or multiple fuel cell layers, each
layer comprising anodes, cathodes, and an electrolyte membrane
interposed between the anodes and cathodes. A fuel cell system
which includes such a cellular layer typically includes a means for
supplying air to the cathodes and a means for supply or fuel or
other reactant fluid to the anodes at an acceptable pressure
level.
[0004] In many electrochemical cell systems, such as fuel cell
systems, reactant plenums include a flow distribution network, or
flow field, to direct the flow of fuel across the electrochemical
cell layer. This adds complexity, cost and volume to the design.
However, with a single inlet the size of the electrochemical cell
layer that can be serviced without a flow field is very limited,
since the need to uniformly distribute fuel to the fuel absorbing
anodes requires non-uniform flow profiles within the cavity. Such
non-uniform flow profiles have negative effect on fuel cell
operation. In particular, this sets up gradients of water flux and
heat transfer within the electrochemical cell layer leading to
uneven power production, and hence degraded performance and
lifetime.
SUMMARY
[0005] Embodiments of the present invention relate to a fluid
distribution system. The system may include one or more
electrochemical cell layers, a bulk distribution manifold having an
inlet, a cell layer feeding manifold in direct fluidic contact with
the electrochemical cell layer and a separation layer that
separates the bulk distribution manifold from the cell feeding
manifold, providing at least two independent paths for fluid to
flow from the bulk distribution manifold to the cell feeding
manifold.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] In the drawings, like numerals describe similar components
throughout the several views. The drawings illustrate generally, by
way of example, but not by way of limitation, various embodiments
discussed in this patent document.
[0007] FIG. 1 illustrates an exploded view of an electrochemical
cell system, as constructed in accordance with at least one
embodiment.
[0008] FIG. 2 illustrates a cross-sectional view of a fluidic
controller in an open-valve state, as constructed in accordance
with at least one embodiment.
[0009] FIG. 3A illustrates a cross-sectional view of portions of an
electrochemical cell system, such as along line 3A-3A of FIG. 1,
and an associated uniform fuel flow, as constructed in accordance
with at least one embodiment.
[0010] FIG. 3B illustrates a conceptualization of uniform fuel flow
velocity present within the electrochemical cell system of FIG. 3A,
which includes an array of fluidic controllers and an array of
anode cavity inlets, as constructed in accordance with at least one
embodiment.
[0011] FIG. 4 illustrates a cross-sectional view of a low pressure
system plenum of a fuel cell system, such as along line 4-4 of FIG.
3A.
[0012] FIG. 5 illustrates a system layout of a fluidic control
system with at least one embodiment.
[0013] FIG. 6 illustrates a block flow diagram of a method for
operating a fuel cell system with at least one embodiment.
[0014] FIG. 7 illustrates a block flow diagram of a method for
operating a fuel cell system utilizing a fluidic controller array
with at least one embodiment.
DETAILED DESCRIPTION
[0015] The following Detailed Description includes references to
the accompanying drawings, which form a part of the Detailed
Description. The drawings show, by way of illustration, specific
embodiments in which the present systems, assemblies, and methods
may be practiced. These embodiments, which are also referred to
herein as "examples," are described in enough detail to enable
those skilled in the art to practice the present systems,
assemblies, and methods. The embodiments may be combined, other
embodiments may be utilized or structural or logical changes may be
made without departing from the scope of the present systems,
assemblies, and methods. The following Detailed Description is,
therefore, not to be taken in a limiting sense and the scope of the
present systems, assemblies, and methods are defined by the
appended claims and their legal equivalents.
[0016] In this document, the terms "a" or "an" are used to include
one or more than one, the term "or" is used to refer to a
nonexclusive "or" unless otherwise indicated, and the phrase
"electrical component(s)" is used to include portable electronic
devices, such as but not limited to, cellular phones, satellite
phones, laptop computers, computer accessories, displays, personal
audio or video players, medical devices, televisions, transmitters,
receivers, lighting devices including outdoor lighting or
flashlights, electronic toys, or any device conventionally used
with batteries. Additionally, it is to be understood that the
phraseology or terminology employed herein, and not otherwise
defined, is for the purpose of description only and not of
limitation. Furthermore, all patents and patent documents referred
to in this document are incorporated by reference herein in their
entirety, as though individually incorporated by reference. In the
event of inconsistent usages between this document and those
documents so incorporated by reference, the usage in the
incorporated references should be considered supplementary to that
of this document; for irreconcilable inconsistencies, the usage in
this document controls.
[0017] Embodiments of the invention relate to a fluidic apparatus
that be can be integrated in a variety of architectures to
dynamically adjust conditions along the surface of an
electrochemical layer to provide high-performance conditions unique
to localized regions of the cell layer. The electrochemical cell
layer may be a fuel cell layer, for example. The apparatus or
distribution system may be operable with other devices of the
electrochemical cell system to protect a cell layer from
potentially destructive or non-efficient fluid conditions by
stabilizing a reactant flow in response to a local fluid condition
prior to exposing the cell layer, mitigate catastrophic failure of
entire cell assemblies during failure events of individual cells,
and operate to optimize fluid flow conditions of the cell assembly
responsive to modes of operation of the overall system.
[0018] Various fluid systems can be integrated within the
electrochemical cell system to deliver reactants for the reaction
and remove products. Stacked electrochemical layer assemblies
include multiple electrochemical cell units and alternating fluid
delivery layers for providing reactant to reaction sites along a
surface of each electrochemical cell unit. Planar array
architectures receive reactants from a surface of a common
electrochemical cell layer for multiple cells in the array and
similarly remove product from the opposing surface of the
electrochemical layer. Arrays may be flexible and have conformal
architectures to any suitable surface. Other geometric
architectures include enclosed reactant plenums such as
tubular-shaped plenums formed completely or in part by the
electrochemical cell layer that can receive fluid for the fuel
cells.
[0019] A fluid distribution system or device including optional
fluidic controllers, and related systems and methods are provided
herein. Fluidic controllers may include pressure regulator
components, flow controllers, on/off valves, flow restrictors,
pressure drop materials, ports, inlets, outlets, combinations
thereof, or any device capable of affecting one or more properties
of a fluid in a fuel cell system, such as flow rate or pressure. As
one example, use of the device allows for the dimensions of a
single fuel cell layer to be increased or the dimensions of the
fuel cell system otherwise changed arbitrarily without resulting in
a non-uniform fuel flow to the anodes of the cellular layer. As
another example, the fluidic device allows for uniform
concentration gradients along reactant into and through the
reactant plenum of an anode or cathode surface of an
electrochemical cell layer without requiring the use of explicit
flowfield plates, thereby reducing the overall size and potentially
the cost of the fuel cell system. As yet another example, the array
of fluidic controllers allows for localized control of fuel or
other fluid pressure applied to localized regions and may include a
layered structure providing relatively easy, economically feasible,
and volumetric-friendly fuel cell system manufacture
DEFINITIONS
[0020] As used herein, "fluidic controller" refers to any device
capable of affecting one or more properties of a fluid in a fuel
cell system, such as flow rate or pressure. Examples of fluidic
controllers include pressure regulator components, flow
controllers, on/off valves, flow restrictors, pressure drop
materials or combinations thereof.
[0021] As used herein, "electrochemical layer" refers to a sheet
including one or more active functional members of an
electrochemical cell. For example, an electrochemical layer may
include a fuel cell layer. As used herein, "active functional
members" refers to components of an electrochemical cell that
function to convert chemical energy to electrical energy or convert
electrical energy to chemical energy. Active functional members
exhibit ion-conductivity, electrical conductivity, or both,
[0022] As used herein, "electrochemical cell" refers to a device
that converts chemical energy to electrical energy or converts
electrical energy to chemical energy. Examples of electrochemical
cells may include galvanic cells, electrolytic cells,
electrolyzers, fuel cells, batteries and metal-air cells, such as
zinc air fuel cells or batteries. Any suitable type of
electrochemical cell including fuel cells and appropriate materials
can be used according to the present invention including without
limitation proton exchange membrane fuel cells (PEMFCs), solid
oxide fuel cells (SOFCs), molten carbonate fuel cell (MCFCs),
alkaline fuel cells, other suitable fuel cells, and materials
thereof. Further examples of fuel cells include proton exchange
membrane fuel cells, direct methanol fuel cells, alkaline fuel
cells, phosphoric acid fuel cells, molten carbonate fuel cells or
solid oxide fuel cells.
[0023] An electrochemical cell layer, such as a fuel cell layer,
may include one or more anodes, cathodes, and electrolyte
interposed between the anodes and cathodes. In a fuel cell system,
the cathodes may be supplied with air containing oxygen for use as
an oxidizing agent, and the anodes may be supplied with hydrogen,
for example, for use as fuel. The oxidizing agent may be supplied
from air surrounding the fuel cell system, while the fuel or other
reactant fluid may be supplied from the fluid reservoir.
[0024] Arrays of unit cells can be constructed to provide
varied-power generating electrochemical cell layers in which the
entire electrochemical structure is contained within the layer.
This means additional components such as plates for collecting
currents etc. can be eliminated, or replaced with structures
serving different functions. Structures like those described herein
are well adapted to be manufactured by continuous processes. Such
structures can be designed in a way which does not require the
mechanical assembly of individual parts. In some embodiments, the
conductive path lengths within this structure may be kept extremely
short so that ohmic losses in the catalyst layer are minimized.
Array may refer to a plurality of individual unit cells. The
plurality of cells may be formed on a sheet of ion exchange
membrane material, a substrate, or may be formed by assembling a
number of components in a particular manner.
[0025] Unit cells according to the invention may be used in a
planar electrochemical cell layer that is conformable to other
geometries, as described in application Ser. No. 11/185,755, filed
on 21 Jul. 2004, entitled "DEVICES POWERED BY CONFORMABLE FUEL
CELLS" and application Ser. No. 60/975,132, filed 25 Sep. 2007,
entitled "FLEXIBLE FUEL CELL," which are hereby incorporated by
reference.
[0026] Arrays can be formed to any suitable geometry. Examples of
planar arrays of fuel cells are described in co-owned U.S.
application Ser. No. 11/047,560 filed on 2 Feb. 2005 entitled
"ELECTROCHEMICAL CELLS HAVING CURRENT CARRYING STRUCTURES
UNDERLYING ELECTROCHEMICAL REACTION LAYERS", the disclosure of
which is herein incorporated by reference. Fuel cells in an array
can also follow other planar surfaces, such as tubes as found in
cylindrical fuel cells. Alternately or in addition, the array can
include flexible materials that can be conformed to other
geometries.
[0027] As used herein, "fluid" refers to a continuous, amorphous
substance whose molecules move freely past one another and that has
the tendency to assume the shape of its container. A fluid may be a
gas, liquefied gas, liquid or liquid under pressure. Examples of
fluids may include fluid reactants, fuels, oxidants, and heat
transfer fluids. Fluid fuels used in fuel cells may include
hydrogen gas or liquid and hydrogen carriers in any suitable fluid
form. Examples of fluids include air, oxygen, water, hydrogen,
alcohols such as methanol and ethanol, ammonia and ammonia
derivatives such as amines and hydrazine, silanes such as disilane,
disilabutane, complex metal hydride compounds such as aluminum
borohydride, boranes such as diborane, hydrocarbons such as
cyclohexane, carbazoles such as dodecahydro-n-ethyl carbazole, and
other saturated cyclic, polycyclic hydrocarbons, saturated amino
boranes such as cyclotriborazane, butane, borohydride compounds
such as sodium and potassium borohydrides, and formic acid.
[0028] As used herein, "fluid enclosure" may refer to a device for
storing a fluid. The fluid enclosure may store a fluid physically
or chemically. For example, the fluid enclosure may chemically
store a fluid in active material particles. A fluid enclosure may
also refer to a fluid enclosure including active material particles
and an outer enclosure wall, conformably coupled to the fluid
storage component and may also include structural fillers. Examples
of such a fluid enclosure are found in commonly-owned U.S. patent
application Ser. No. 11/473,591, filed Jun. 23, 2006, whose
disclosure is incorporated by reference herein in its entirety.
[0029] As used herein, "active material particles" refer to
material particles capable of storing hydrogen or other fluids or
to material particles that may occlude and desorb hydrogen or
another fluid. Active material particles may include fluid storing
materials that occlude fluid, such as hydrogen, by chemisorption,
physisorption or a combination thereof. Some hydrogen-storing
materials desorb hydrogen in response to stimuli, such as change in
temperature, change in heat or a change in pressure. Examples of
hydrogen-storing materials that release hydrogen in response to
stimuli, include metal hydrides, chemical hydrides, suitable
micro-ceramics, nano-ceramics, boron nitride nanotubes, metal
organic frameworks, palladium-containing materials, zeolites,
silicas, aluminas, graphite, and carbon-based reversible
fluid-storing materials such as suitable carbon nanotubes, carbon
fibers, carbon aerogels, and activated carbon, nano-structured
carbons or any combination thereof. The particles may also include
a metal, a metal alloy, a metal compound capable of forming a metal
hydride when in contact with hydrogen, alloys thereof or
combinations thereof. The active material particles may include
magnesium, lithium, aluminum, calcium, boron, carbon, silicon,
transition metals, lanthanides, intermetallic compounds, solid
solutions thereof, or combinations thereof.
[0030] As used herein, "metal hydrides" may include a metal, metal
alloy or metal compound capable of forming a metal hydride when in
contact with hydrogen. Metal hydride compounds can be generally
represented as follows: AB, AB.sub.2, A.sub.2B, AB.sub.5 and BCC,
respectively. When bound with hydrogen, these compounds form metal
hydride complexes.
[0031] As used herein, "composite hydrogen storage material" refers
to active material particles mixed with a binder, wherein the
binder immobilizes the active material particles sufficient to
maintain relative spatial relationships between the active material
particles.
[0032] As used herein, "occlude" or "occluding" or "occlusion"
refers to absorbing or adsorbing and retaining a substance, such as
a fluid. Hydrogen may be a fluid occluded, for example. The fluid
may be occluded chemically or physically, such as by chemisorption
or physisorption, for example.
[0033] As used herein, "desorb" or "desorbing" or "desorption"
refers to the removal of an absorbed or adsorbed substance.
Hydrogen may be removed from active material particles, for
example. The hydrogen or other fluid may be bound physically or
chemically, for example.
[0034] As used herein, "contacting" refers to physically,
chemically, electrically touching or within sufficiently close
proximity. A fluid may contact an enclosure, in which the fluid is
physically forced inside the enclosure, for example.
[0035] Embodiments of the present invention relate to a fluid
distribution system. The system may include one or more
electrochemical cell layers, each layer having a first side and a
second side and each layer having one or more electrochemical
cells, a bulk distribution manifold having an inlet, a cell layer
feeding manifold in direct fluidic contact with the electrochemical
cell layer and a separation layer that separates the bulk
distribution manifold from the cell feeding manifold, providing at
least two independent paths for fluid to flow from the bulk
distribution manifold to the cell feeding manifold. The bulk
manifold may further include an outlet. The fluid distribution
system may also include a primary pressure regulator coupled to the
inlet of the bulk distribution manifold.
[0036] The fluid distribution manifold may be a layered structure,
for example. One or more components of the system may be features
formed by one or more of the processes of etching, stamping, laser
cutting, die cutting, deposition, printing, machining, molding, or
electroforming a feature on the one or more featured layers. The
featured layers may be sealed by one or more of gluing, adhesive
bonding, thermal bonding, diffusion boding, welding, soldering the
featured layers together or combinations thereof, for example.
[0037] The system may include one or more fluidic controllers in
contact with the at least two independent paths. The fluidic
controllers may be pressure regulator components, flow controllers,
on/off valves, flow restrictors, pressure drop materials or
combinations thereof. Each controller may include two or more
featured layers, each layer including an array of features
associated therewith. The features from a first featured layer may
be interactively associated with features from a second featured
layer. The one or more fluidic controllers may co-planar with one
another. Co-planar may include being positioned on the same side of
layer on integrated within the same layer. The layer itself may be
bent or shaped in any number of configurations, such as a cylinder.
The fluidic controllers may act independently of one another.
[0038] The fluid distribution system may also include a primary
pressure regulator coupled to the inlet of the bulk distribution
manifold, wherein the one or more fluidic controllers include
secondary pressure regulator components and wherein the primary
pressure regulator component and the secondary pressure regulator
component operate at different pressures.
[0039] The at least two independent paths may be spatially
distributed within the separation layer. Spatially distributed may
include any number of patterns or configurations. A fluid enclosure
may be coupled to the bulk distribution manifold. The bulk
distribution manifold may include a segmented manifold configured
to direct fluid to the at least two independent paths. The cell
feeding manifold may include at least two discrete regions, each
region served by at least one fluidic controller. The cell feeding
manifold may be in direct fluidic contact with an anode side or
cathode side of the one or more electrochemical cell layers.
[0040] Embodiments of the invention also relate to an
electrochemical cell system, including one or more electrochemical
cell layers, each layer having a first side and a second side and
each layer having one or more electrochemical cells, one or more
fluid plenums fluidically coupled to a first side of the one or
more fuel cell layers and two or more fluidic controllers coupled
to at least one of the one or more fluid plenums. The one or more
electrochemical cell layers may be fuel cell layers. The one or
more fluid plenums may include at least two reactant plenums, each
of the reactant plenums associated with one or more of the fluidic
controllers. In addition, each of the reactant plenums may be
associated with a single fluidic controller. Alternatively, each of
the reactant plenums may be associated with one or more
electrochemical cell units of the electrochemical cell layers. The
fluid plenums may be fuel plenums, for example. A fuel in contact
with the fuel plenums may include hydrogen. The fuel may also
include alcohols, amines, silanes, complex metal hydride compounds,
boranes, hydrocarbons, carbazoles, saturated cyclic and polycyclic
hydrocarbons, saturated amino boranes or combinations thereof.
[0041] At least two of the two or more fluidic controllers may be
fluidically coupled to a common fluid manifold. The one or more
electrochemical cell layers may include at least two
electrochemical cell sets, each electrochemical cell set including
at least two electrically serially-coupled electrochemical cell
units, wherein the at least two electrochemical cell sets are
arranged in an electrically serial configuration, an electrically
parallel configuration, or a combination thereof.
[0042] As discussed above, the fluidic controllers may be used
with, among other things, a fuel cell system 100, such as the fuel
cell system illustrated in FIG. 1. In this example, the fuel cell
system 100 includes, but is not limited to, one or more of a fuel
cell layer 102, fluidic controllers 104, a charge port or inlet
106, a fluid reservoir 108, or a current collecting circuit 110. In
one example, the fluid reservoir 108 is filled with fuel by
pressurizing the charge port or inlet 106. In another example,
power from the fuel cell layer 102 is utilized by the current
collecting circuit 110, which collects the power from the fuel cell
layer 102 and routes it out of the fuel cell system 100.
[0043] FIG. 2 illustrates a cross-sectional view of one example of
a fluidic controller 104, an array of which may be used to reduce
the primary fluidic pressure emanating from the fluid reservoir 108
to the second fluidic pressure used by a surface of the fuel cell
layer. The fluidic controllers 104 include inlets to communicate
fuel reservoir and the fuel cell layer at localized regions within
a reactant plenum.
[0044] Fluid manifolds for fuel cells having stacked architectures
may include external or internal manifolding along the stack to
deliver fluid to an inlet of each flow field. The flow controllers
include a high-pressure inlet and two or more outlets in fluid
communication with localized regions of the recant plenum and
arranged along a surface of a fuel cell layer. Instead of relying
on a single inlet for delivering reactant to the cell layer, a
fluidic device can be used to provide active and variable control
of independent reactant flows in response to local conditions along
the surface of the fuel cell layer, as shown in FIGS. 3A-3B.
Reactant delivery can be facilitated on-demand responsive to the
localized conditions along the cell layer. The fluid device
delivers stoichiometric reactant flows to unit cells or groups of
localized unit cells--even along lower surface areas, this allows
localized cells to consume reactant according to their
capability.
[0045] Referring again to FIG. 3A, each of the fluidic controllers
104 in the array 402 serves to control the flow of fuel or other
fluid from the bulk flow manifold 108 to the fuel plenum 302. If
control of the flow is based on maintaining uniform pressure in the
fuel plenum 302, then each pressure regulator may act independently
of one another to maintain such uniform pressure. In one such
example, the fluidic controllers 104 are actuated electronically,
such as by way of a feedback mechanism, in which case parts of the
electrochemical cell layer may turned on and off as desired. In
this way, long standby time operation of the electrochemical cell
system 100 may be achieved.
[0046] As shown in FIG. 3B, when multiple inlets 406 to the surface
of the electrochemical cell layer from the low pressure outlets 216
of the array 402 of fluidic controllers 104 are employed, such as
in a parallel configuration, there is advantageously a fluid (e.g.,
fuel) flow velocity that is uniform or nearly uniform along a
length and width of the fuel cell layer 102.
[0047] As shown in FIG. 4, the fluidic controllers 104 may be
spatially distributed so that each fluidic controller distributes
fuel or other fluid into localized regions of the fuel plenum 302.
The fuel plenum 302 may be an anode cavity. Optionally, the fuel
plenum 302 could be partitioned into a number of discrete regions
502A, 502B, 502C, etc. as shown, with each region served by one or
more fluidic controllers 104. Alternatively, the fuel plenum 302
could be a single plenum with multiple inlets 406.
[0048] In operation, fuel or other fluid is allowed to enter the
fluid device via a charge port or inlet 106. As shown in
cross-section in the example of FIG. 3A, a dual control system, is
shown including an electrochemical cell layer having a reactant
plenum separated from a bulk flow manifold 108 by the array of
fluid controllers. In one example, the dual system plenum 404 has
approximately the same dimensions as the fuel cell layer 102, with
the electrochemical cell layer 102 in direct fluidic communication
with the cell layer surface. The reservoir 108 may be a fluid
plenum, such as a bulk distribution plenum.
[0049] The electrochemical cell system may include one or more
electrochemical cell layers, a reactant plenum fluidically coupled
to the one or more electrochemical cell layers, a bulk flow
manifold and one or more arrays of fluidic controllers coupled to
the reactant plenum. One or more inlet fluidic controllers may be
coupled to the bulk flow manifold. Two or more outlet controllers
may be positioned between the bulk flow manifold and the reactant
plenum. Optionally, there may be a fluidic controller or other
fluid control element at such inlet. Fluidic controllers 104 may
control the fluidic (e.g., fuel) pressure coming out of the fluid
reservoir 108 by reducing a primary (higher) fluidic pressure
present in the fluid reservoir 108 to a more constant secondary
(lower) fluidic pressure for delivery to the electrochemical cell
layer 102, and more specifically, the anodes 112. The fluidic
controllers 104 may also control other properties of a fluid or the
fluid distribution system, such as flow rate, pressure, volume,
etc.
[0050] Referring to FIG. 5, a system layout 600 of a fluid control
system is illustrated. In an option, the fluidic control system
includes one or more of a fuel refueling inlet 604, a check valve
component 608, a pressure selection valve 616, an on/off valve 610,
and/or an outlet 622, for example, to a fuel cell. The on/off valve
610 turns off the fuel supply if the electrochemical cell system is
turned off The fuel system further optionally includes a connection
602 to a fuel reservoir.
[0051] The fluidic control system optionally includes at least one
fluidic controller, such as a pressure regulator component 612,
620, 624. In an example, the at least one pressure regulator
component 612, 620, 624 includes at least one primary pressure
regulator component 614. In a further option, the at least one
pressure regulator component 612, 620, 624 includes at least one
primary pressure regulator component 614 and/or at least one
secondary pressure regulator component 618, 626. In an option, the
fluidic control system, includes multiple pressure regulator
components 612, 620, 624 such as multiple secondary pressure
regulator components 618, 626, or an array of secondary pressure
regulator components 618, 626 alone or in combination with the
primary pressure regulator component.
[0052] When the electrochemical cell fed by the system is able to
tolerate wide variations in inlet pressure, or when the difference
between the fluid storage pressure, such as fuel storage pressure,
and the demanded delivery pressure is low, a primary pressure
regulator component, such as a single, primary pressure regulator
component, may be used. When the electrochemical cell fed by the
system is unable to tolerate wide variations in pressure, the
system can be configured with both primary and secondary
regulators.
[0053] The primary pressure regulator component 614 steps the
pressure down for the secondary pressure regulator component 618,
626. Further, the primary pressure regulator component 614 reduces
the effect of fluctuating fuel reservoir pressure on the output of
the secondary pressure regulator components 618, 626. The primary
pressure regulator component 614 and the secondary pressure
regulator component 618, 626, and/or the two or more secondary
pressure regulator components 618, 626 can be set to different
output pressures. In this configuration, one of the regulators can
provide a lower pressure for when the electrochemical cell is in
standby operation, while another can provide a higher pressure when
the electrochemical cell is actively operating. This option can be
extended to include multiple pressures tuned to support a wide
range of operating modes of the electrochemical cells, including
the modulation of pressures for ancillary electrochemical cell
management functions such as gas purging, water management etc.
Using multiple secondary pressure regulator components allows for
digital selection of the operating pressures, and eliminates a need
for a continuously variable pressure regulation system.
[0054] In an option, the pressure selection valve 616 controls flow
to the higher pressure secondary regulator 618, 626 and controls
the pressure of the linked output of the multiple secondary
regulators 618, 626. If the pressure selection valve 616 is off,
the output of the secondary pressure regulator components 618, 626
is at the lower pressure, while if the valve 616 is open, the
output will be at the higher pressure. In an option, one or both of
the secondary regulators 618, 626 are pilot pressure controlled
from the fuel pressure at the electrochemical cell. This allows for
the fuel pressure at the electrochemical cell to remain constant,
unaffected by pressure losses in the fuel conduits between the
regulators 612, 620, 624 and the electrochemical cell.
[0055] As mentioned above, two or more secondary regulators 618 can
be included in the fluidic control system. For example, an array of
parallel secondary regulators 618 with each having its own pressure
selection valve would enable digital pressure control where the
pressure can be increased and decreased in increments. The
regulators 618 in the array would each have differing output
pressure.
[0056] The electrochemical cell pressure is easily fed back through
the conduit back to the physical location of the pressure regulator
components. Additionally, the unregulated gas pressure can be used
to provide mechanical power into the system for actuation of valves
due to the multiple stages. This allows for the system to operate
with a minimum of external energy inputs.
[0057] Advantageously, this invention allows for high fuel or other
fluid pressures, such as pressures exceeding 30 psi, to exist in
the fluid reservoir 108 as these high pressures are never allowed
to exert a force on the surface of the electrochemical cell layer
102 due to the array of fluidic controllers 104. This means an
overall high pressure bulk fuel distribution system may be
employed, allowing for easy circulation of fuel or other fluid
within the fluid reservoir 108 and avoiding the possibility of
having local starvation of fuel or other powering fluid.
Optionally, multiple high pressure fluid reservoirs may be
connected to a common inlet so that multiple electrochemical cell
layers can be operated as a single system. This allows each
electrochemical cell layer to be individually pressure regulated,
eliminating the need for pressure distribution management and
allowing for an alternative method of constructing multiple
electrochemical cell layer assemblies.
[0058] The one or more electrochemical cell layers may include a
plurality of electrochemical cells electrically serially-coupled to
form electrochemical cell sets. Each may include a first plurality
of electrochemical cell sets that are electrically coupled to form
a first group of parallel-coupled electrochemical cell sets, a
second plurality of electrochemical cell sets that are electrically
coupled to form a second group of parallel-coupled electrochemical
cell sets. The first group may be electrically serially-coupled to
the second group. The sets may be fuel cell sets, for example.
[0059] The fluid device can be operated to reduce flow to localized
regions of the reactant plenum proximal to failed cell units or
cell sets. An unusually large consumption rate of the
electrochemical cell (i.e. a compromised or ruptured electrolyte)
may trigger a valve in fluid communication with the localized area
to shut off. Blocking diodes between any parallel cell units or
sets would prevent reverse currents flowing through them.
[0060] A fluid is often provided from a fluid enclosure at
pressures in excess of those tolerable by an electrochemical cell
layer. A high pressure bulk distribution system may be employed,
allowing for easier circulation of fuel or other fluid with a fluid
reservoir or plenum and avoids the possibility of having local
starvation of fuel or other powering fluid. Optionally, multiple
high pressure fluid reservoirs may be connected to a common inlet
so that multiple fuel cell layers can be operated as a single
system. Each electrochemical cell layer may then be individually
regulated, such as pressure regulated, eliminating the need for
pressure distribution management and allowing for an alternative
method of constructing multiple electrochemical cell
assemblies.
[0061] In the example of FIG. 2, the fluidic controller 104
includes a layered structure having one or more featured layers
200. The featured layers 200 each include features thereon or
therein. The features provide one or more portions of the fluidic
controller 104. When the featured layers 200 are disposed adjacent
to one another, features on one layer are brought together with
features of another layer; for example, the features are brought
physically or functionally together. When the features from
different layers 200 are brought together, the fluidic controller
104 may be formed. The first featured layer and the second featured
layer may be brought together by stacking, for example.
[0062] As shown in FIG. 2, the one or more featured layers 200 may
include, but are not limited to, a first layer 202, a second layer
204, a third layer 206, and a fourth layer 208. In this example,
the second layer 204 is disposed between the first layer 202 and
the third layer 206, and the third layer 206 is disposed between
the second layer 204 and the fourth layer 208. The featured layers
200 may be combined in such a way that the fluidic controller 104
is defined, in part, by a first side 210 and a second side 212. In
one example, the first layer 202 forms the first side 210 and
includes a low pressure outlet 216, while the fourth layer 208
forms the second side 212 and includes a high pressure inlet 214.
The first side 210 and the second side 212 may be configured to
cooperatively interact with adjacent components of the
electrochemical cell system 100 (FIG. 1), such as an anode cavity
disposed between the fluid reservoir 108 (FIG. 1) and the
electrochemical cell layer 102 (FIG. 1) and the fluid reservoir 108
(FIG. 1), respectively. Notably, fewer or more than four layers may
be used to create the fluidic controller 104, the layers may be
formed of relatively thin sheets of material, and multiple fluidic
controllers 104 may be formed on the same layers, resulting in an
array of co-planar or substantially co-planar regulators (see FIG.
3A).
[0063] Referring again to the first layer 202, it can serve a
number of functions, and may include a number of features thereon.
In one example, the first layer 202 provides a cap 218 to a low
pressure regulator plenum 220, where the low pressure regulator
plenum 220 is formed between the first layer 202 and the second
layer 204. In various examples, the first layer 202 includes an
elastically deformable material, and further may actuate a
regulator valve 222 through an actuation member 224 via the
elastically deformable material. The first layer 202 may further
provide an elastic spring force to counteract the force from
pressure in the low pressure regulator plenum 220. In one example,
the elastic stiffness of the first layer 202 determines the output
pressure of the fluidic controller 104. The actuation member 224,
in this example, is disposed through an opening 226 of the second
layer 204.
[0064] As shown, the actuation member 224 provides a contact
between the regulator valve 222 and the elastically deformable
material of the first layer 202. In one example, the actuation
member 224 includes a member that is disposed between the regulator
valve 222 and the first layer 202. In another example, the
actuation member 224 is formed on or as part of the first layer
202. In another example, the actuation member 224 may be formed
integrally or as part of the third layer 206. In yet another
example, the actuation member 224 includes a sphere or a ball
disposed between the first layer 202 and the regulator valve 222.
When pressure in the low pressure regulator plenum 220 drops below
the desired output pressure of the fluidic controller 104, the
elastic material of the first layer 202 presses against the
actuation member 224 causing the regulator valve 222 to open.
[0065] Referring to the second layer 204, it may include a number
of features such a portion of the low pressure regulator plenum
220, and separates the low pressure regulator plenum 220 from a
high pressure regulator plenum 228. In another example, the second
layer 204 further provides a sealing seat 230 for the regulator
valve 222. The third layer 206 may define a portion of the high
pressure regulator plenum 228, in further cooperation with the
second layer 204 and the fourth layer 208. In this example, the
third layer 206 further includes the regulator valve 222.
[0066] The regulator valve 222 seals the opening 226 within the
fluidic controller 104. In one example, the regulator valve 222 is
formed with the third layer 206, such that the regulator valve 222
is integral with the third layer 206 without the need for
additional, discrete components. In another example, the regulator
valve 222 formed with the third layer 206 may also serve as the
actuation member 224. In a further example, the regulator valve 222
includes a valve body 232, a valve seal 234, and a valve spring
member 236. The valve body 232 may have the valve seal 234 therein,
for example, via molding. The valve body 232 is coupled with the
valve spring member 236, for example a cantilever spring, which
allows for the regulator valve 222 to be moved from a closed
position to an open position, and from the open position to the
closed position. The valve spring member 236 can be formed by
etching such member in the third layer 206 allowing for a
spring-like attachment within the third layer 206. Other options
for the valve spring member 236 include, but are not limited to, a
deformable member such as a ball, an elastomeric or deflectable
region on the fourth layer 208, a member, such as a deformable
member below the regulator valve 222, or as part of the fourth
layer 208.
[0067] In the example shown, the valve spring member 236 and the
regular valve 222 are disposed within the high pressure regulator
plenum 228. A fourth layer 208 of the fluidic controller 104 is
disposed adjacent to the third layer 206, and caps the outer
portion of the regulator valve 222, for example the bottom of the
regulator valve 222, and optionally provides the high pressure
inlet 214 for the fluidic controller 104. The high pressure inlet
214 is fluidly coupled with the high pressure regulator plenum 228,
and the low pressure outlet optionally provided by the first layer
202 is fluidly coupled with the low pressure regulator plenum 220,
for instance, through ports disposed within the second layer 204
and the third layer 206.
[0068] In an example operation of the fluidic controller 104,
fluid, such as a fuel, enters the high pressure inlet 214 and
pressurizes the high pressure regulator plenum 228. The fuel or
other fluid further passes through the normally open regulator
valve 222 into the low pressure regulator plenum 220. As the low
pressure plenum 220 increases in pressure, the first layer 202 is
deflected outward until the actuation member 224 pulls free from
the regulator valve 222, closing the regulator valve 222 against
the sealing seat 230, and limiting pressure in the low pressure
regulator plenum 220. Pressure in the low pressure regulator plenum
220 drops as the fuel or other fluid in the low pressure regulator
plenum 220 drains through the low pressure outlet port 216. This
causes the first layer 202 to deflect back to its inward position,
causing the actuation member 224 to reopen the regulator valve 222
and start the cycle over again.
[0069] The fluidic controller 104 shown in FIG. 2 is further
discussed in U.S. patent application Ser. No. 12/053,374, which was
filed on 21 Mar. 2008, entitled "FLUIDIC CONTROL SYSTEM AND METHOD
OF MANUFACTURE," and published as U.S. Patent Pub. 2008/0233446,
and which is incorporated herein by reference in its entirety. As
discussed in 2008/0233446, the layered structure of the fluidic
controllers 104 may also include other flow control elements, such
as one or more valves or check valves.
[0070] In various examples, the fluidic controllers 104 used in the
array 402 include a layered structure having one or more featured
layers 200 (FIG. 2), as further discussed in association with FIG.
2. Notably, FIG. 2 illustrates just one example of a suitable thin
pressure regulator for use in the array 402. It is contemplated
that that other thin pressure regulators or pressure regulating
nano-structured materials could also be used in the array 402. As
an example, large scale materials or multiple apertures may be
utilized.
[0071] Referring to FIG, 6, a block flow diagram 700 of a method of
operating a electrochemical cell system is shown, with at least one
embodiment. A high pressure plenum may be fluidically coupled 702
to a low pressure plenum. One or more electrochemical cell layers
may be coupled 704 to the low pressure plenum.
[0072] Fluidically coupling 702 the high pressure system plenum to
the low pressure system plenum may include using at least two
fluidic controllers. The at least two controllers may be disposed
such that the controllers are substantially co-planar with one
another or function independently of one another. The array of
fluidic controllers may be spatially distributed between the high
pressure system plenum and the low pressure system plenum.
[0073] Referring to FIG. 7, a block flow diagram 800 of a method of
operating a electrochemical cell system utilizing a fluidic
controller array is shown, with at least one embodiment. A reactant
flow may be supplied 802. The reactant flow may be distributed 804
within one or more plenums through a fluidic controller array to
localized regions within one or more reactant plenums through one
or more arrays of fluidic controllers and in proximity to one or
more electrochemical cell layers. The reactant flow may be
contacted 806 with one or more electrochemical cell layers.
[0074] Supplying 802 may also include regulating the reactant flow.
Regulating may include changing a flowrate of the reactant. The
flowrate may be changed in response to a change in power demand of
the one or more electrochemical cell layers or unit electrochemical
cells in each layer, in response to a change in performance of the
one or more electrochemical cell layers or unit electrochemical
cells in each layer, or in response to a failure of the one or more
electrochemical cell layers or unit electrochemical cells in each
layer.
[0075] Distributing 804 may include regulating the reactant flow
within one or more reactant plenums. Regulating may include
changing the pressure of the one or more reactant plenums. The
pressure may be changed in response to a change in power demand of
the one or more electrochemical cell layers or unit electrochemical
cells in each layer, in response to a change in performance of the
one or more electrochemical cell layers or unit electrochemical
cells in each layer, or in response to a failure of the one or more
electrochemical cell layers or unit electrochemical cells in each
layer.
[0076] Use of an array of fluidic controllers allows for the
dimensions of a single electrochemical cell layer to be increased
or otherwise changed arbitrarily without resulting in non-uniform
fuel flow to one or more anodes of a electrochemical cell layer. On
a similar note, the array of fluidic controllers allows for the
uniform flow of fuel into and through the anode cavity without
requiring the use of explicit flowfield plates, thereby reducing
the overall size and potentially the cost of a electrochemical cell
system. A uniform fuel flow to the anodes advantageously results in
constant electrical component performance. The array of fluidic
controllers additionally allows for localized control of an optimal
fuel pressure applied to the anodes, while the fluid reservoir can
be designed for bulk transport of fuel or other reactant fluids
without concern for the effects of the bulk transport pressures on
the anodes. Furthermore, the array of fluidic controllers may
include a layered structure providing relatively easy, economically
feasible, and volumetric-friendly electrochemical cell system
manufacture.
[0077] It is to be understood that the above Detailed Description
is intended to be illustrative, and not restrictive. For instance,
any of the aforementioned examples may be used individually or with
any of the other examples. Many other examples may be apparent to
those of skill in the art upon reviewing the above description. As
one example, the present assemblies and methods may find use with
other fluidic transfer applications, such as non-fuel or reactant
based fluidic applications, where fluid supply at an acceptable
pressure with localized control may be desirable. Therefore, the
scope of the present systems, assemblies, and methods should be
determined with reference to the appended claims, along with the
full scope of legal equivalents to which such claims are entitled.
In the appended claims, the terms "including" and "in which" are
used as the plain-English equivalents of the respective terms
"comprising" and "wherein." Also, in the following claims, the
terms "including" and "comprising" are open-ended, that is, a
system, assembly, article, or process that includes elements in
addition to those listed after such a term in a claim are still
deemed to fall within the scope of such claim.
* * * * *